UINavigationController，如何在第二級viewController中隱藏tabbar然後在第三級viewController中顯示tabbar

Question

這裏是我的一段代碼，但這樣，當我推動第三級視圖控制器時，tabbar不會顯示。

//at first level 
SecondLevelViewController *_2vc = [[SecondLevelViewController alloc]initWithNibName:@"SecondLevelViewController" bundle:nil]; 
    _2vc.hidesBottomBarWhenPushed = YES; 
    [self.navigationController pushViewController:_2vc animated:YES]; 

//at second level 
ThirdLevelViewController *_3vc = [[ThirdLevelViewController alloc]initWithNibName:@"ThirdLevelViewController" bundle:nil]; 
    _3vc.hidesBottomBarWhenPushed = NO; 
    [self.navigationController pushViewController:_3vc animated:YES]; 

Answer 1

相反，當你初始化視圖控制器設置hidesBottomBarWhenPushed的值，則應改爲處理中的隱藏機制 - （空）viewWillAppear中：（BOOL）在視圖控制器，而不是動畫。

這種實現的一個例子是：

在SecondLevelViewController.m

-(void)viewWillAppear:(BOOL)animated 
{ 
    [_bottomBar setHidden:YES]; 
} 

在ThirdLevelViewController.m

-(void)viewWillAppear:(BOOL)animated 
{ 
    [_bottomBar setHidden:NO]; 
} 

Answer 2

// Load the view 
    AddViewController *aController = [[AddViewController alloc] init]; 

    // Set the view title 
    aController.title = @"Add View"; 

    // hide tabbar 
    aController.hidesBottomBarWhenPushed = YES; 

    // add it to stack. 
    [[self navigationController] pushViewController:aController animated:YES]; 

-(void)viewWillAppear: (BOOL)animated 
{ 
    [super viewWillAppear:animated]; 
    [self.tabBarController.tabBar setHidden:YES]; 
} 

-(void)viewWillDisappear: (BOOL)animated 
{ 
    [super viewWillDisappear:animated]; 
    [self.tabBarController.tabBar setHidden:NO]; 
}